Lighting fixture diffuser with brightness control



June 8, 1965 w. L. uPscoMB 3,138,452

LIGHTING FIXTURE DIFFUSER WITH BRIGHTNESS CQNTROL Filed April 1, 1963 2 Sheets-Sheet l INVENTOR WILLIS L. Ll PS COMB BY mox8 mmc June 8, 1965 W. L. LIPSCOMB LIGHTING FIXTURE DIFFUSER WITH BRIGHTNESS CONTROL Filed April 1, 1963 2 Sheets-Sheet 2 Fig.6

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INVENTOR. WILLIS L. LIPSCOMB United States Patent 3,188,462 LIGHTING FIXTURE DIFFUSER WITH BRHGHTNES CONTRGL Wiilis L. Lipscomb, 529 Sprecides iildg, San Diego, Caiif. Fiied Apr. 1, 1963, Ser. No. 269,568 Ciaims. (El. Mitt-'78) The present invention relates generally to lighting fixtures and more particularly to a lighting fixture diffuser with brightness control.

The primary object of this invention is to provide a lighting fixture diifuser for luminaires of the elongated type, that is, the type that are, ordinarily associated with fluorescent lamps, which may be made with hollow walls for lightness as well as permitting reflective coating to be applied internally for protection against wear and damage.

A further object of the invention is to provide a lighting fixture diffuser which is particularly adapted for fabrication from light weight plastic material by an extrusion process.

A still further object of the invention is to provide a lighting fixture diffuser which can be economically pro duced in a variety of shapes suitable for use in luminaires or lighting fixtures as either a side panel or bottom panel or a combination thereof.

Finally, it is an object to provide a lighting fixture diffuser with brightness control which is simple and convenient to use and which will give generally eficient and durable service.

With these and other objects definitely in view, this invention consists in the novel construction, combination and arrangement of elements and portions, as will be hereinafter fully described in the specification, particularly pointed out in the claims, and illustrated in the drawings which form a material part of this disclosure, and in which:

FIGURE 1 is a fragmentary side elevation view of a lighting fixture;

FIGURE 2 is an enlarged sectional View taken on line 22 of FIGURE 1;

FIGURE 3 is an enlarged sectional view of a single inclined fin and fragmentary sectional view of an adjacent portion of the wall of the lighting fixture difliuser;

FIGURE 4 is an enlarged sectional view of a typical extruded fin;

FIGURE 5 is a view, similar to FIGURE 4, of an alternative fin structure;

FIGURE 6 is a fragmentary sectional View of a lighting fixture difiuser with a wall having light control means thereon; and

FIGURE 7 is a sectional view, similar to FIGURE 6, with an outer closure wall added as an alternative feature.

Similar characters of reference indicate similar or identical elements and portions throughout the specification and throughout the views of the drawing.

FIGURE 1 shows a portion of a luminaire assembled from a plurality of diffusers constructed in accordance with the present invention. Each diffuser 10 encloses one or more fluorescent lamps 12 mounted in the usual brackets 14 which are suspended from box 16 containing the usual ballast and starting system which is conventional in lamps of this type. Boxes 16 may be suspended from the ceiling by hangers 18 or they may be flush mounted. Boxes 16 are also provided with supports 2t) from which are suspended the diffusers It). As shown in FIGURE 1 a series of difiusers may be assembled in endwise relationship.

The improved difiuser of the present invention consists basically of a transparent or translucent wall member 24 of suitable thickness from which extends a plurality of parallel fins which are attached to and supported by said wall member by their bases only. In other words, the fins extend horizontally and in one direction only, that is, uninterrupted by cross ribs, in contradistinction to the prior art egg crate cellular panel structures. The cross section of the ribs may vary but are illustrated as hollow V-shaped transparent fins 26 extending longitudinally of the wall member 24 as shown in FIGURE 1. Fins 26 may extend laterally at an oblique angle to the wall member 24, as shown by the side panels in FIGURE 2 and in detail in FIGURE 3, or they may extend normal to the wall member as shown at 25 by the top and bottom panels in FIGURE 2 and in detail in FIGURE 6. The particular angle is not critical and is determined primarily by the light control desired in each luminaire.

Divergent legs 28, 28 of fins 25, 26 define, with Wall 24, an enclosed space 30. The Walls of this space are provided with a light reflective coating 32 of any desired characteristics. i

The bottom panel of the diffuser shown in FIGURE 2 is formed of light transmitting material with integral solid V-shaped fins 27. The outside surface of this panel may be wholly or partly coated with a light reflective material. As here shown the sides only of the fins are coated as at 29. The bottom panel is suitably secured to the side panels 24 by cementing or other well known means.

Diffuser panels 10 may be formed by any of the well known methods of plastic forming. For example, hollow fins 2.5, 26 may be formed to the desired size and shape and then bonded to wall members. However, I have found it more economical particularly in the manufacture of a large number of similar units to utilize an extruding machine with a die cut to extrude the wall member 24- and hollow fins 25, 26 as a unitary element. Reflective coating 32 may be applied to the interior of the fins by spraying or by other well know methods such as vapor deposition.

If desired a plastic end plate 34 may be applied to the exposed end of diffuser 10. Metal end plate 36 suitably secured to supports 20 completes the assembly.

FIGURE 5 shows an alternative form of providing the hollow fins with a reflective material. In this form the space is completely filled with an aluminum powder 38 or other similar flowable reflective or opaque material. In this alternative form the fin 37 is shown as rectangular in cross section rather than triangular.

FIGURE 6 discloses the use of one form of brightness control means applied to the surface of wall 24 opposite from the fins. Molded into the surface are prismatic ridges or dimples 42 which function to refract the light rays emanating from lamps 12 thereby providing degree of brightness control. It will be obvious that various brightness control means may be applied to or incorporated in the Wall member 24 or in the second wall member 44- mentioned below, this brightness control means including various coatings as well as regular and irregular deformation of the surfaces of the wall members.

A further form of the invention is shown in FIGURE 7. This is generally similar to the previous forms described. In this form the diffuser is provided with a second wall member 44 which is formed integrally with the distal pointed ends or bases of V-shaped fins 26. This unit has particular utility where an extremely rigid structure is desired.

It is to be understood that the rectangular cross sectional shape of my diffuser, as shown in FIGURE 2, is representative only. This shape may vary depending upon the ornamental effect desired and the type of light control required. For example, the entire diffuser may be constructed from several panels bonded or secured together, or the entire diffuser may be formed as a unitary item, by plastic extrusion preferably, and the overall cross-sectional shape may vary from the reca) tangular form shown acording to the dictates of use, aesthetic elTect desired and the economics of production.

It is understood that minor variation from the form of the invention disclosed herein may be made without departure from the spirit and scope of the invention, and that the specification and drawings are to be considered as merely illustrative rather than limiting.

I claim:

1. A lighting fixture diffuser comprising:

an elongated substantially rigid light transmitting Wall member and said wall member having on one side thereof and as unitary portions thereof a plurality of elongated, imperforate parallel, hollow, light transmitting fins, the proximal ends of the legs of the said fins being unitary with the wall member, all said fins extending horizontally and in one direction only and laterally from one side of said wall member and longitudinally thereof to form an enclosed space therewith;

and a reflective coating applied to the interior surfaces of said fins.

2. A lighting fixture diffuser as claimed in claim 1 in which the fins are V-shaped and are positioned obliquely to the surface of the wall member.

3. A lighting fixture difluser as claimed in claim 1 in which the fins are positioned normal to the surface of the wall member.

4. A lighting fixture diffuser comprising:

structure according to claim 1; and brightness control means unitary with and disposed on the opposite side of said wall member.

5. A lighting fixture diffuser comprising:

structure according to claim 1 wherein said fins are similar and have their distal pointed ends in a common plane;

and a second light transmitting wall member parallel to the first mentioned wall member and extending in said plane and unitary with said distal pointed ends of the fins.

References Cited by the Examiner UNITED STATES PATENTS D. 122,694 9/40 Rubinstein 2407 8 2,242, 872 5/41 Rolph 240-78 2,427,084 9/ 47 Alderman 2405 1 2,510,346 6/50 Nitardy 240-78 2,745,001 5 5 6 Guth 2409 2,817,752 12/57 Florence 24078 2,913,576 11/59 Gilleard 2409 2,918,567 12/ 59 Leitz 240-9 2,971,083 2/ 61 Phillips et a1 240-78 NORTON ANSHER, Primary Examiner. 

1. A LIGHTING FIXTURE DIFFUSER COMPRISING: AN ELONGATED SUBSTANTIALLY RIGID LIGHT TRANSMITTING WALL MEMBER AND SAID WALL MEMBER HAVING ON ONE SIDE THEREOF AND AS UNITARY PORTIONS THEREOF A PLURALITY OF ELONGATED, IMPERFORATE PARALLEL, HOLLOW, LIGHT TRANSMITTING FINS, THE PROXIMAL ENDS OF THE LEGS OF THE SAID FINS BEING UNITARY WITH THE WALL MEMBER, ALL SAID FINS EXTENDING HORIZONTALLY AND IN ONE DIRECTION ONLY AND LATERALLY FORM ONE SIDE OF SAID WALL MEMBER AND LONGITUDI- 